The proposed research will be the first prospective epidemiologic study of diabetes and cardiovascular disease incidence involving both Mexican Americans and non-Hispanic whites. The hypotheses to be tested focus on the body fat distribution and hyperinsulinemia as independent risk factors for these diseases. The study design will also permit testing for residual ethnic differences in incidence of diabetes after accounting for known and postulated risk factors. Approximately 3500 subjects, ages 25-64 at baseline, (60% Mexican American and 40% non-Hispanic white) will be reexamined 6-8 years after their initial examination. Baseline measures include: lipids and lipoproteins, glucose tolerance tests, serum insulin concentrations, blood pressures, resting electrocardiograms, genetic marker data, medical history data including medications, dietary histories, health habits including smoking histories and extensive psychosocial and acculturation data. Anthropometric data include multiple skinfolds, body diameters and body circumferences which will permit assessment of central vs. peripheral and upper vs. lower body fat distribution. Endpoints include diabetes, sudden cardiac death, non-fatal (including silent) myocardial infarction, angina pectoris, cerebrovascular and peripheral vascular disease. All subjects will be invited to attend a survey examination where they will have fasting lipid and lipoprotein determinations, a glucose tolerance test to diagnose incident cases of diabetes according to National Diabetes Data Group criteria, blood pressure measurements, a resting electrocardiogram, and will complete a questionnaire designed to elicit information on possible cardiovascular endpoints. Hospital and/or physician records will be obtained and standardized criteria such as those used in the Community Cardiovascular Surveillance Project (CCSP) will be used to validate endpoints. Subjects giving a history of peripheral vascular disease or diabetes will have ankle/arm blood pressure ratios determined before and after exercise. Deaths will be ascertained in the course of routine follow-up supplemented by search of state health department and the National Death Index records. Death certificates will be requested, and for those certificates indicating diabetes or cardiovascular disease as the cause of death, appropriate hospital and/or physician records will be requested and reviewed. Standardized criteria will be used to validate cause of death.